Method and device for draining humidity from insulation

ABSTRACT

A method and device for drawing off humidity, such as condensation fluid, from an insulation layer around apparatuses, such as pipe lines and the like. The method is characterized in that a hollow body, such as a sleeve is arranged in a passage in the insulation material, and where a number of openings in the wall portion of the hollow body or the sleeve communicates with the surroundings outside the insulation layer, whereby condensation fluid can be drawn off from the insulation layer to the surroundings via the hollow body in the form of the sleeve.

The present invention relates to a method and device for drawing offhumidity, such as condensed humidity (condensation fluid), frominsulation layers around apparatuses, pipe conduits and the like, as areindicated in the introduction to the subsequent claims 1 and 8,respectively. The invention thus has to do with a novel construction ofan insulation system for draining or drawing off condensation fluid.

The method and device are especially intended for application fordraining any moisture/condensation from insulation materials which arearranged around apparatuses and pipe lines in which fluids, such asliquids and gas are conveyed or stored, or in apparatus where processesoccur which involve being able to form condensation on the surface ofthe apparatus or the pipe line. Such condensation is formed on the hotside of a boundary surface between a cold fluid and a hot gas fluid whenthe latter includes a condensable gas. In the present instance, when acolder fluid is conveyed through a pipe line while the surroundingsrepresent the hotter fluid, the pipe outer wall constitutes saidboundary surface (the hot side).

It is usual to arrange a mantle of insulation around pipe lines whichconvey fluids. In addition to the insulating effect, the insulationlayer also provides protection against mechanical damage. Usually themantle of insulation comprises a sleeve-shaped layer of the insulationmaterial itself which surrounds the pipe. The outer side of theinsulation material is usually covered by a thinner cover layer in theform of weather-protecting cover cloth, that is to say a metal orplastic layer. The cover layer can be water-tight so that water, fromrain and the like, does not penetrate into the insulation itself. Thedrawback with the sealed cover layer is however that it also involvescondensation being able to be simultaneously locked inside theinsulation, which can entail the occurrence of corrosion on the pipesurfaces. Furthermore the insulating effect of the insulating materialis reduced as a result of the accumulated moisture.

GB patent application No. 2.220.459 discloses a pipe surrounded by awater repellant insulation material and an outer cover. The insulationmaterial includes profiles on its outer surface, thus forming a patternof cavities beneath the cover. Water entering the cover may evaporatedue to the heat from inside the pipe, and may return outwards throughthe cover. Thus this patent publication does not relate to the solvingof the same problem as the present invention, where cold fluids beingtransfered through pipes resulting in the formation of liquid watercondensation, and where a need exist to remove the humidity from theinsulation by ventilation.

If the fluid has a higher temperature than the surrounding air theinsulation contributes to prevent heat losses from the pipe line. Andcorrespondingly, if the fluid has a lower temperature, the insulationprevents a rise in temperature of the pipe fluid. When air having atemperature higher than the temperature of the pipe fluid comes intocontact with the pipe wall, a portion of the air humidity will condenseagainst the colder pipe surface. This problem with condensation which isconfined within the insulation material applies of course not only inconnection with pipe lines, but also in connection with fluid-carryingapparatuses, such as tanks, containers and the like (for example inconnection with refrigerating plants) where these are insulated in asimilar fashion so as to prevent heat transfer between the fluid withinthe tank or the container and the surroundings.

In the following the expression drain is employed so as to cover beingable to vent the insulation of moisture-containing air, and being ableto draw off liquid state condensation water, by employing the deviceaccording to the invention.

It is an object of the present invention to provide a method and adevice which can prevent or reduce the problems which arise inconnection with such condensation within pipe line insulations.

It is also an object of the present invention to provide a device whichcan also contribute to a lower venting of any humidity (such assteam-formed humidity) in the insulation itself. This means thatcondensation, both in liquid and steam form can escape the insulation.

The method according to the present invention is characterised by thefeatures which are evident from the characterised portion of thefollowing claim 1, and preferred embodiments are indicated in thedependent claims 2-7.

The device according to the present invention is characterised by thefeatures which are evident from the characterised portion of thefollowing claim 8, and preferred embodiments are indicated in thedependent claims 9-13.

The device according to the present invention is defined as a hollowspace-forming body, and according to the most preferred embodiment thisbody is designed as a sleeve having a through duct. The duct itself thusconstitutes the above-defined hollow space, while the one of the ductopenings of the sleeve constitutes the said at least one opening whichforms a connection between the hollow space and the surroundings outsidethe insulation layer.

The invention shall now be explained further with reference to theaccompanying Figures, wherein:

FIG. 1 shows a perspective view of a construction of the drain deviceaccording to the invention.

FIG. 2 shows a cross-section of the drain sleeve according to FIG. 1.

FIGS. 3 and 4 show respectively a perspective view and a cross-sectionof an insulated pipe where the drain sleeve comes into use.

As is evident from FIG. 1, the drain sleeve 10 comprises an elongatepipe or a sleeve which forms a hollow internally elongate and throughpassage 12. In the one end portion the sleeve 10 comprises a flange orbase portion 14.

Along the length of the whole sleeve 10 there are arranged a number ofopenings or bores through the wall of the sleeve. The openings can forma regular or irregular pattern. On the outer side of the sleeve thereare further arranged a number of elevations 18. The elevations have aform like barbs which cause the sleeve to be slidably displaced relativeto a woven or other surface, the one way, but will have a tendency tostick on slide displacement the other way. The elevations can thuscomprise studs 18 projecting outwardly from the surface of the sleevewhich face outwards and backwards in a direction towards the flange 14.

In FIG. 1 the drain sleeve is illustrated in the form of a pipe having acircular cross-section, but the drain sleeve can have othercross-sections, for example it can be more oval or polygonal.

The drain sleeve 10 according to the invention is preferably made ofplastic, and it can be made in alternative ways, such as by injectionmoulding, or by extrusion with subsequent working in order to form interalia the openings in the pipe wall. It is an advantage to employ asleeve material which has a low heat conductivity.

In order to be able to adjust the length of the drain sleeve accordingto the current need, the sleeve is divided into a number of sleevesections 20 a,20 b,20 c. Each sleeve section 20 a,20 b,20 c is separatedfrom adjacent sleeve sections by a groove or a depression which isarranged around the periphery of the sleeve, and which functions as afissure or attenuation line). The grooves 22 are formed by the wallthickness of the sleeve in this portion being somewhat less than in theremaining sleeve portion. A sleeve section can be readily separated fromthe sleeve by cutting off along a groove.

The sleeve illustrated in FIG. 1 can have a total length of 100 mm. Foreach 1 cm. a groove can be designed and by cutting off according to needthe precisely suitable drain sleeve can be produced, that is to saycompletely down to a length of 20 mm. As a cutting tool there can beemployed a conventional sharp knife, illustrated at 24. According to apreferred embodiment the outer end of the sleeve which is situatedoutside the insulation comprises a dome-shaped (convex) end portionhaving a centrally disposed opening hole which has smaller transversedimensions than the internal cross-section of the sleeve, and throughwhich opening condensation water can freely flow outwards from thesleeve.

In FIG. 2 there is illustrated a cross-section of the sleeve seen fromabove. The passage 12, the openings 16, the sleeve wall, thebase-forming flange 14 and the rows of barbs 18 are evident from FIG. 2.

In FIGS. 3 and 4 there are shown a cross-section and a partiallongitudinal section of an insulated pipe, for example a steel pipe,where the drain sleeve is well suited for use.

According to an example the pipe 30 conveys a fluid in its internalspace 32. On the outside of the pipe 30 there is surroundingly arrangedan insulation 34 having a given layer thickness, and an outer coverlayer (a mantle) 36 is arranged coveringly on the outside of theinsulation.

The drain sleeve 10 according to the invention shall now be employed fordraining out condensation water which lies in the insulation, andespecially completely inside at the surface of the pipe. First anopening is made in the cover layer, and by means of a suitable tool apassage 38 is now made through the insulation material 34 forwardstowards the pipe wall. The passage through the pipe wall has a somewhatsmaller diameter than the diameter of the sleeve. Now the drain sleeve10 is cut so that it has the correct length and reaches almost forwardto the outer wall of the pipe 30. The end of the sleeve is thrust intothe mouth of the duct 38 through the cover layer, and the sleeve isinserted into the duct until the flange 14 halts the inward movement ofthe sleeve in that it pushes against the outer surface of the coverlayer. During the insertion the insulation material is forced somewhatto the side, and the barbs are infiltrated in the adjacent fibres of theinsulation material. Thereby the sleeve cannot fall out of the passageby itself.

Now the sleeve is mounted, and any occurring condensation water and/ormoist air can flow into the duct 12 through the holes 16 through thewall, and condensation water can run along the inside of the sleevetowards its mouth and out as drops, illustrated at 40 in FIG. 3. For thecondensation water to be able to run out by the force of gravity, thedrain sleeve is preferably installed according to the invention frombelow through the insulation material and upwards towards the overlyingpipe wall. In order to obtain a sufficient diversion of condensation, anumber of such drain sleeves are installed in a corresponding manner inthe insulation in a regular or irregular pattern along the pipe 30.

In order to obtain a general venting of moisture from the insulation, itis also possible to install such drain sleeves around the wholeperiphery of the insulation/pipe. Since the installation of a sleeve canto a certain degree in itself reduce the ability to insulate of theinsulation layer, this circumstance, that is to say how tightly theinstalled sleeves are placed, must therefore be considered precisely ineach individual case.

The drain sleeve can now remain standing as a permanent drain sleeve inthe insulation of the pipe, and uniformly draw off condensation from theinsulation material.

In that condensation water can now be removed by means of a single drainsleeve which at the same time will involve a certain drying up of theinsulation, the danger of the attack of corrosion is heavily reduced onthe pipe material 30. Besides the insulating effect of the insulationmaterial will be greatly enhanced when it is now kept in a drier andairier condition.

The invention is not to be limited to applying the special design of apipe or a sleeve for drawing off condensation from the insulation. Thusthere can generally be used a hollow space-forming body, such as isdefined in the dependent claims, and which can have a number of openingsin the wall for the admission of condensation to the hollow space, andat least one opening which can release the condensation further outwardsto the surroundings. This means that the body can have many alternativeexternal forms. For example the body can be rectangular or polygonal.However a pipe or sleeve shape will be the most practical and preferredform of the present invention.

What is claimed is:
 1. A method for drawing off humidity, includingcondensation fluid, from a layer of insulation material aroundapparatuses, pipe lines and the like, comprising the steps of: a.providing one or more hollow, space-forming bodies, each said hollow,space-forming body comprising a wall portion having a plurality ofopenings; b. creating one or more passages extending into the interiorof the insulation material; and c. arranging one of said hollow,space-forming bodies in each said passage in the insulation materialsuch that at least one of said openings communicates with the insulationmaterial and at least one of said openings communicates with thesurroundings outside the layer of insulation material, whereby thehumidity can be drawn off from the layer of insulation material to thesurroundings via the hollow body.
 2. The method according to claim 1,wherein said hollow, space-forming body is a sleeve having a throughduct, and whereby a plurality of openings in the wall portion of saidsleeve form a fluid connection between said duct and the insulationmaterial, and further whereby one end of said duct is in communicationwith the surroundings outside the layer of insulation material, suchthat the humidity can be drawn off through said openings into said ductand further to the surroundings.
 3. The method according to claim 2,further comprising the step of adapting the length of said sleeve to thelayer thickness of the insulation material prior to arranging saidsleeve in said passage.
 4. The method according to claim 3, furthercomprising the step of arranging said sleeve in said passage so that onesleeve end is positioned substantially adjacent to the surface of theapparatus/pipe line and the other sleeve end projects extending outapproximately in the boundary region between the surroundings and thesurface of the insulation layer.
 5. The method according to claim 4,wherein said sleeve further comprises a stop flange at one end which isadapted, during installation of said sleeve, to impact against the outersurface of the insulation material.
 6. The method according to claim 5,wherein said sleeve further comprises anchoring means which prevent saidsleeve from sliding out from the insulation layer after said sleeve isinstalled.
 7. The method according to claim 6, wherein said anchoringmeans comprise a plurality of barbs projecting from the wall portion ofsaid sleeve, said barbs being adapted to engage with the insulationmaterial.
 8. The method according to either of claims 1-7, wherein saidpassage is created from below and upwards into the insulation material,whereby humidity in the liquid state may be drawn off by the force ofgravity.
 9. A device for use in an insulation system for drawing offhumidity, including condensation fluid, from a layer of insulationmaterial around apparatuses, pipe lines and the like, comprising: a. ahollow, space-forming body having a wall portion, said hollow,space-forming body being adapted to be arranged in the layer ofinsulation material; b. a plurality of openings in said wall portion, atleast one of which forms a connection between the hollow space and theinsulation, and at least one of which forms a connection between thehollow space and the surroundings outside the insulation layer; and c.anchoring means for preventing the body from sliding out from theinsulation after it is installed.
 10. The device according to claim 9,wherein said hollow, space-forming body is a sleeve with a through duct,and wherein a plurality of openings in the wall portion of said sleeveform a fluid connection between said duct and the insulation, such thatthe humidity can be drawn off into and further through said duct to thesurroundings.
 11. The device according to claim 10, wherein saidanchoring means comprise barbs projecting from the wall portion of saidsleeve, said barbs being adapted to infiltrate the adjacent fibers ofthe insulation material.
 12. The device according to claim 11, furthercomprising a stop flange arranged at one end of said sleeve, such that,during installation, said stop flange will impact against the outersurface of the insulation material.
 13. The device according to claim12, wherein said sleeve is divided into a plurality of selectivelyremovable segments, such that the length of said sleeve may be cut downby removing one or more of said segments.
 14. The device according toclaim 13, wherein said selectively removable segments are formed bymeans of grooves or attenuation lines integrated around thecircumference of the wall portion of said sleeve.